Not applicable.
Not applicable.
Not applicable.
1. Field of the Invention
The present invention relates, in general, to sawmills in the lumber industry, and in particular, to resaw apparatus used in sawmills to cut boards off of log cants.
2. Information Disclosure Statement
Sawmills often employ so-called xe2x80x9cresawxe2x80x9d apparatus to saw boards from a succession of log cants, which are logs that have been cut into substantially rectangular or square shape. Well-known solutions for such resaw apparatus include band saws that saw boards from the bottom of the cants, and such resaw apparatus are known to cause a succession of cants to circulate past the band saw in successive passes in a forward direction only on a conveyor belt or rollers, such that the cants pass through the band saw and then are moved onto recirculation belts or rollers and then recirculated around the band saw and back to the infeed of the saw for the next pass through the saw. Such an approach, known as a xe2x80x9crun-aroundxe2x80x9d cant feed system, has the disadvantage that only a single board is cut off each of the succession of cants as they pass through the band saw, causing the sawmill operator to lose familiarity with a given cant as other cants are processed before the next pass of the given cant through the band saw, thereby causing less optimal cutting decisions to be made for each cant than would otherwise be possible if a given cant were processed to completion before moving to the next cant. Additionally, because the boards in most prior art resaw systems are sawed from the bottom of the cant, the sawmill operator is prevented from viewing the grade of the wood that is about to be cut into a board, thereby preventing optimal decisions by the sawmill operator as to when the cant should be turned to another face in order to maximize the grade of wood being cut from the cant. Additionally, such a xe2x80x9crun-aroundxe2x80x9d system occupies excessive space in a sawmill because of the recirculation of the cants back to the infeed of the saw after each cut.
It is therefore desirable to have an improved resaw apparatus that allows the sawmill operator to process each cant to completion before beginning the resaw process on the next cant, that permits the sawmill operator to view the grade of wood about to be cut from each cant, and that occupies less floor space than prior-art xe2x80x9crun-aroundxe2x80x9d cant feed systems.
A preliminary patentability search in Class 83, Subclasses 794, 788, 813, 703, 155.1, 707, 166, 871, 820, and 731, and Class 144, Subclass 378, produced the following patents, some of which may be relevant to the present invention: Edgar, U.S. Pat. No. 524,135 (issued Aug. 7, 1894); Sprague, U.S. Pat. No. 1,344,096 (issued Jun. 22, 1920); Foreman, U.S. Pat. No. 1,487,649 (issued Mar. 18, 1924); Wirstrom, U.S. Pat. No. 3,850,061 (issued Nov. 26, 1974); Poetzsch et al., U.S. Pat. No. 4,030,386 (issued Jun. 21, 1977); Pryor et al., U.S. Pat. No. 4,253,361 (issued Mar. 3, 1981); Weinzierl, U.S. Pat. No. 4,289,180 (issued Sep. 15, 1981); Albright, U.S. Pat. No. 4,732,184 (issued Mar. 22, 1988); Kirbach, U.S. Pat. No. 4,926,917 (issued May 22, 1990); Jones et al., U.S. Pat. No. 5,088,363 (issued Feb. 18, 1992); and Raybon et al., U.S. Pat. No. 5,722,474 (issued Mar. 3, 1998).
Edgar, U.S. Pat. No. 524,135, discloses a sawmill in which a cant reciprocates back and forth upon a carriage past a fixed band saw having a vertical cutting blade.
Sprague, U.S. Pat. No. 1,344,096, discloses a band saw having a horizontal cutting blade, and a cant passes past the cutting blade so that a board is cut from the bottom of the cant.
Foreman, U.S. Pat. No. 1,487,649, discloses a band saw in which cants pass without reciprocation past the saw blade. A board is cut from the bottom of the cant, and the cants xe2x80x9cloop aroundxe2x80x9d and make successive passes past the saw blade.
Wirstrom, U.S. Pat. No. 3,850,061, discloses a band saw that makes horizontal cuts through a horizontally-reciprocating piece of plastic. Cuts are made in both directions of reciprocation, and the saw moves vertically to make successive cuts.
Poetzsch et al., U.S. Pat. No. 4,030,386, discloses a band saw that makes horizontal cuts through a horizontally-reciprocating piece of plastic. Cuts are made in both directions of reciprocation, and the saw moves vertically to make successive cuts.
Pryor et al., U.S. Pat. No. 4,253,361, discloses a sawmill in which cants move past a circular vertical saw blade, with various mechanisms being shown for flipping and turning the cants.
Weinzierl, U.S. Pat. No. 4,289,180, discloses a band saw having a horizontal cutting blade that cuts boards from the top of stationery cants. The band saw moves vertically to accomplish successive cuts.
Albright, U.S. Pat. No. 4,732,184, discloses a lumber saw-sizing machine in which four band saws operate on a piece of lumber as the lumber is fed through the machine without reciprocation. A hold-down roller holds the log in place during sawing.
Kirbach, U.S. Pat. No. 4,926,917, discloses use of optical measuring devices in the context of a sawmill.
Jones et al., U.S. Pat. No. 5,088,363, discloses a sawmill having multiple close-spaced horizontal band saws in which the cant is not reciprocated past the band saws.
Raybon et al., U.S. Pat. No. 5,722,474, discloses a sawmill having a computerized scanning station that scans dimensions of logs.
Additionally, Fast Line Saw Systems, Inc., of Central City, Ky., is known to advertise a band saw in combination with a re-saw system under the trademark Fast Line Gator 204 Resaw with Run-around System, typical of other so-called xe2x80x9crun-aroundxe2x80x9d resaw equipment that do not have a reciprocating workpiece but instead has the cant make multiple forward passes only through the band saw by passage on a conveyor system that circulates the cant around the band saw in a well-known xe2x80x9crun-aroundxe2x80x9d cant feed configuration.
None of these references, either singly or in combination, disclose or suggest the present invention.
The present invention is an improved resaw apparatus for sawing boards from log cants, in which the cant is reciprocated past a band saw that removes boards from the top of the cant as the cant moves in a first direction past the band saw. A raker gate catches each newly-sawn board from the top of the cant as the cant reciprocates in the reverse direction in preparation for the next pass through the band saw.
It is an object of the present invention to provide an improved resaw apparatus that removes boards from the top of log cants and that processes each cant to completion before sawing of the next cant is begun. It is a further object of the present invention to provide a resaw apparatus that is more compact than prior art resaw apparatus and that uses less floor space in a sawmill than prior art xe2x80x9crun-aroundxe2x80x9d cant feed configuration resaw apparatus.